Explanation

Red lead, also known as lead lead lead, bright pink, guangming pill, zhangdan, and red lead oxide, whose scientific name is lead pentoxide, is an orange crystal or scale, or an amorphous powder. It is a kind of compound mixed with lead monoxide and lead dioxide, with high density, and belongs to alkaline pigment. red lead is insoluble in water and alcohol, but can be dissolved in nitric acid, hot hydrochloric acid and hot lye. This pigment has excellent resistance to corrosion and rust, as well as high temperature, but is not resistant to acid environment. When reacting with free fatty acids in the paint base, red lead will form lead soap, which makes the paint have good covering power and adhesion. In addition, red lead can also react with hydrogen sulfide to form black lead sulfide. Exposed to the air, it also gradually turns into lead carbonate. When heated to 500 ° C, red lead decomposes into lead monoxide and oxygen. red lead is an excellent anticorrosive pigment, which is often used to coat onshore steel products to provide excellent antirust effect. However, in recent years, due to the strengthening of environmental protection laws and regulations, the use of red lead as a anticorrosive pigment has declined significantly. In addition, red lead is also used to manufacture refined glass, light source glass and optical glass, especially in the manufacture of picture tube glass shells.

Classification